1 | function y = minus(X,Y) |
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2 | %MINUS (overloaded) |
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3 | |
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4 | % Author Johan Löfberg |
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5 | % $Id: minus.m,v 1.2 2006/08/11 11:48:15 joloef Exp $ |
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6 | |
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7 | if isa(X,'sdpvar') |
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8 | X = ncvar(struct(X)); |
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9 | elseif isa(Y,'sdpvar') |
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10 | Y = ncvar(struct(Y)); |
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11 | end |
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12 | |
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13 | X_is_ncvar = isa(X,'ncvar'); |
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14 | Y_is_ncvar = isa(Y,'ncvar'); |
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15 | |
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16 | switch 2*X_is_ncvar+Y_is_ncvar |
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17 | case 1 |
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18 | if isempty(X) |
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19 | try |
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20 | y = full(X - reshape(Y.basis(:,1),Y.dim(1),Y.dim(2))); |
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21 | catch |
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22 | error(lasterr); |
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23 | end |
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24 | return |
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25 | end |
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26 | |
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27 | y = Y; |
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28 | n_Y = Y.dim(1); |
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29 | m_Y = Y.dim(2); |
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30 | [n_X,m_X] = size(X); |
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31 | x_isscalar = (n_X*m_X==1); |
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32 | y_isscalar = (n_Y*m_Y==1); |
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33 | any_scalar = x_isscalar | y_isscalar; |
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34 | |
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35 | % Speeeeeeed |
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36 | if x_isscalar & y_isscalar |
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37 | y.basis = -y.basis; |
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38 | y.basis(1) = y.basis(1)+X; |
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39 | % Reset info about conic terms |
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40 | y.conicinfo = [0 0]; |
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41 | return |
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42 | end |
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43 | |
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44 | if any_scalar | ([n_Y m_Y]==[n_X m_X]) |
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45 | if y_isscalar |
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46 | y.basis = repmat(y.basis,n_X*m_X,1); |
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47 | y.dim(1) = n_X; |
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48 | y.dim(2) = m_X; |
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49 | end |
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50 | y.basis = -y.basis; |
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51 | if nnz(X)~=0 |
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52 | y.basis(:,1) = y.basis(:,1)+X(:); |
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53 | end |
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54 | else |
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55 | error('Matrix dimensions must agree.'); |
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56 | end |
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57 | % Reset info about conic terms |
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58 | y.conicinfo = [0 0]; |
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59 | |
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60 | case 2 |
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61 | |
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62 | if isempty(Y) |
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63 | try |
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64 | y = full(reshape(X.basis(:,1),X.dim(1),X.dim(2))-Y); |
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65 | catch |
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66 | error(lasterr); |
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67 | end |
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68 | return |
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69 | end |
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70 | y = X; |
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71 | n_X = X.dim(1); |
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72 | m_X = X.dim(2); |
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73 | [n_Y,m_Y] = size(Y); |
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74 | x_isscalar = (n_X*m_X==1); |
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75 | y_isscalar = (n_Y*m_Y==1); |
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76 | any_scalar = x_isscalar | y_isscalar; |
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77 | |
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78 | % Silly hack |
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79 | % Taking X-scalar(0) takes unnecessary time |
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80 | % and is used in most definitions of LMIs |
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81 | if (y_isscalar & (Y==0)) |
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82 | return |
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83 | end |
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84 | |
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85 | % Speeeeeeed |
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86 | if x_isscalar & y_isscalar |
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87 | y.basis(1) = y.basis(1)-Y; |
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88 | % Reset info about conic terms |
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89 | y.conicinfo = [0 0]; |
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90 | return |
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91 | end |
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92 | |
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93 | if any_scalar | ([n_Y m_Y]==[n_X m_X]) |
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94 | if x_isscalar |
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95 | y.basis = repmat(y.basis,n_Y*m_Y,1); |
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96 | y.dim(1) = n_Y; |
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97 | y.dim(2) = m_Y; |
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98 | end |
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99 | y.basis(:,1) = y.basis(:,1)-Y(:); |
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100 | else |
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101 | error('Matrix dimensions must agree.'); |
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102 | end |
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103 | |
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104 | % Update information about conic terms |
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105 | % This information is used in DUALIZE to |
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106 | % speed up some checks, and to facilitate some |
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107 | % advanced dualization features. It also |
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108 | % speeds up checking for symmetry in some other code |
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109 | % Ugly, but the best way at the moment |
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110 | % For a description of this field, check SDPVAR code |
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111 | % if (y.conicinfo(1)~=0) & isequal(Y,Y') & (y.conicinfo(2) ~= 2) |
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112 | % y.conicinfo(2) = max(1,y.conicinfo(2)); |
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113 | % else |
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114 | y.conicinfo = [0 0]; |
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115 | % end |
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116 | |
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117 | |
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118 | case 3 |
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119 | |
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120 | % if (X.typeflag~=0) | (Y.typeflag~=0) |
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121 | % error('Relational objects cannot be manipulated') |
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122 | % end |
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123 | |
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124 | n_X = X.dim(1); |
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125 | m_X = X.dim(2); |
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126 | n_Y = Y.dim(1); |
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127 | m_Y = Y.dim(2); |
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128 | x_isscalar = (n_X*m_X==1); |
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129 | y_isscalar = (n_Y*m_Y==1); |
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130 | any_scalar = x_isscalar | y_isscalar; |
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131 | |
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132 | if ~any_scalar |
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133 | if (~((n_X==n_Y) & (m_X==m_Y))) |
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134 | error('Matrix dimensions must agree.') |
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135 | end |
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136 | end |
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137 | |
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138 | all_lmi_variables = uniquestripped([X.lmi_variables Y.lmi_variables]); |
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139 | y = X; |
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140 | X.basis = []; % Returns memory? |
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141 | y.lmi_variables = all_lmi_variables; |
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142 | |
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143 | in_X_logical = ismembc(all_lmi_variables,X.lmi_variables); |
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144 | in_Y_logical = ismembc(all_lmi_variables,Y.lmi_variables); |
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145 | in_X = find(in_X_logical); |
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146 | in_Y = find(in_Y_logical); |
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147 | |
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148 | if isequal(X.lmi_variables,Y.lmi_variables) & n_Y==n_X & m_Y==m_X |
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149 | y.basis = y.basis - Y.basis; |
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150 | % Super special case f(scalar)-f(scalar) |
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151 | if length(X.lmi_variables)==1 |
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152 | if all(y.basis(:,2)==0) |
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153 | y = full(y.basis(1)); |
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154 | else |
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155 | y.conicinfo = [0 0]; |
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156 | end |
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157 | return |
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158 | end |
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159 | else |
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160 | if 1 |
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161 | [ix,jx,sx] = find(y.basis);y.basis = []; |
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162 | [iy,jy,sy] = find(Y.basis);Y.basis = []; |
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163 | mapX = [1 1+in_X]; |
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164 | mapY = [1 1+in_Y]; |
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165 | basis_X = sparse(ix,mapX(jx),sx,n_X*m_X,1+length(all_lmi_variables));ix=[];jx=[];sx=[]; |
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166 | basis_Y = sparse(iy,mapY(jy),sy,n_Y*m_Y,1+length(all_lmi_variables));iy=[];jy=[];sy=[]; |
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167 | else |
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168 | % MATLAB sparse fails on this for huge problems at a certain size |
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169 | basis_X = spalloc(n_X*m_X,1+length(all_lmi_variables),nnz(X.basis)); |
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170 | basis_Y = spalloc(n_Y*m_Y,1+length(all_lmi_variables),nnz(Y.basis)); |
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171 | basis_X(:,[1 1+in_X])=y.basis;y.basis = []; |
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172 | basis_Y(:,[1 1+in_Y])=Y.basis;Y.basis = []; |
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173 | end |
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174 | |
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175 | % Fix addition of matrix+scalar |
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176 | if n_X*m_X<n_Y*m_Y |
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177 | y.dim(1) = n_Y; |
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178 | y.dim(2) = m_Y; |
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179 | basis_X = repmat(basis_X,n_Y*m_Y,1); |
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180 | end |
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181 | if n_Y*m_Y<n_X*m_X |
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182 | y.dim(1) = n_X; |
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183 | y.dim(2) = m_X; |
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184 | basis_Y = repmat(basis_Y,n_X*m_X,1); |
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185 | end |
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186 | |
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187 | % OK, solution is... |
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188 | y.basis = basis_X - basis_Y; |
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189 | end |
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190 | |
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191 | % Only clean if there are variables used in both |
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192 | %if ~all(xor(in_X_logical,in_Y_logical)) |
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193 | % Reset info about conic terms |
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194 | |
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195 | % if (y.conicinfo(1)~=0) & ishermitian(Y) & isempty(intersect(X.lmi_variables,Y.lmi_variables)) |
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196 | % y.conicinfo = [y.conicinfo(2); |
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197 | % else |
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198 | y.conicinfo = [0 0]; |
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199 | % end |
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200 | |
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201 | |
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202 | y = clean(y); |
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203 | %else |
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204 | %end |
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205 | |
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206 | otherwise |
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207 | end |
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208 | |
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209 | % Update info on KYP objects |
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210 | if X_is_ncvar & Y_is_ncvar & X.typeflag==9 & Y.typeflag==9 |
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211 | error('Substraction of KYP objects currently not supported') |
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212 | end |
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213 | if Y_is_ncvar & Y.typeflag==9 |
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214 | y.extra.M = -Y.extra.M+X; |
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215 | y.extra.negated = ~Y.extra.negated; |
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216 | return |
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217 | end |
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218 | if X_is_ncvar & X.typeflag==9 |
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219 | y.extra.M = y.extra.M-Y; |
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220 | return |
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221 | end |
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222 | |
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223 | |
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224 | |
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